1. Field of the Invention
The present invention generally relates to a control system for an outboard motor, and more particularly relates to a control system that controls a steering position, an output power and a shift mode of an outboard motor.
2. Description of Related Art
Watercrafts can carry one or more outboard motors at a stern thereof. The outboard motors typically have a drive unit and a bracket assembly. The bracket assembly supports the drive unit on an associated watercraft for pivotal movement about a steering axis that extends vertically and also for pivotal movement about a tilt axis that extends horizontally.
The drive unit incorporates a propulsion device that propels the watercraft. The propulsion device typically is a propeller. A transmission is incorporated to couple the propulsion device with a prime mover that powers the propulsion device. Typically, the prime mover is an engine. The engine has a throttle valve that regulates an amount of air that is delivered to a combustion chamber of the engine. Normally, output power of the engine varies depending on the amount of the air.
A shift mechanism also is incorporated in the drive unit to move the transmission among forward, reverse and neutral positions that correspond to forward, reverse and neutral modes of the propulsion device, respectively. The propulsion device can propel the watercraft forwardly when the transmission is set in the forward position, while the propulsion device can propel the watercraft backwardly when the transmission is set in the reverse position. The propulsion device does not propel the watercraft when the transmission is set in the neutral position because the propulsion device is disconnected from the prime mover in this position.
A steering wheel is pivotally disposed in a cockpit of the watercraft. A remote controller also is placed in the cockpit of the watercraft. On the other hand, the drive unit employs a control device such as, for example, an electronic control device (ECU). Typically, the steering wheel and the remote controller are electrically connected to the ECU. As thus arranged, the movement of the steering wheel provides a steering position command to the ECU. Also, the movement of the remote controller provides a throttle valve position command and a shift position command to the ECU. The ECU thus controls a steering position of the drive unit, a throttle valve position and the shift position of the transmission based upon the steering position command, throttle valve position command and the shift position command, respectively.
Watercrafts that have the cockpit can enjoy such a control system described above. Relatively small watercrafts, however, do not have such a cockpit and the foregoing control system is not available for those small watercrafts.
Instead, a mechanical controller disposed on the outboard motor side is usable for all types of watercrafts. For example, JP 11-34986 discloses the mechanical controller. A throttle grip is pivotally disposed at one end of a controller housing and is connected to a throttle valve by a mechanical cable. A shift lever is reciprocally disposed at another portion of the controller housing and is connected to a transmission by a mechanical cable. The controller itself can move with a drive unit so as to place the drive unit at a certain steering position.
Due to such separate operating members (i.e., the throttle grip, the shift lever and the controller itself), handling of the controller is somewhat complicated and a human operator needs to be adjusted for handling those different operating members. In addition, because the controller is manually operated through the mechanical cables, a relatively large operating load and/or a moving stroke of each operating member are required. However, the controller does not have enough space to provide the operating members with the operating load and/or the moving stroke. The operator thus may want to have a controller that can more fit his or her desire than such a controller.